Pics, iridium plugs after 24,000

[FJRBluesman]

The coil may donate juice twice as often when sharing plugs; however, the individual plug(s) still only fire very other revolution (4-strokes {a stroke is each time the piston either goes up, or down}, two crank shaft revoltions)... unless you're talking a 2-stroke (one crank shaft revolution).

There's just one little miscalculation in your treatise, Bluesy....it's not the fuel in the cylinder combusting that wears out plugs, it's the spark jumping the gap that wears 'em out, and the shared-coil design fires the plugs every revolution, so (theoretically) an FJR plug WOULD wear out in half the time a non-shared-coil design plug would. So while the plug only ignites the fuel/air charge every other revolution, on the compression stroke, the plug still fires across the spark gap EVERY revolution, compression and exhaust strokes, doubling the "wear out" speed.

I learned something new! :dribble:
I didn't realize this was a wasted spark system. I thought the FeeJ in this day and age of technology was much smarter and had electronic firing via the com-puter. I haven't got into the ignition system of the bike (no need too). OK. I get it, I stand corrected, thanks RH.

 

[mcatrophy]

QUOTE (FJRBluesman @ Jun 15 2010, 08:24 PM) <{POST_SNAPBACK}>

QUOTE (RadioHowie @ Jun 15 2010, 09:06 AM) <{POST_SNAPBACK}>

QUOTE (FJRBluesman @ Jun 15 2010, 11:45 AM) <{POST_SNAPBACK}>

The coil may donate juice twice as often when sharing plugs; however, the individual plug(s) still only fire very other revolution (4-strokes {a stroke is each time the piston either goes up, or down}, two crank shaft revoltions)... unless you're talking a 2-stroke (one crank shaft revolution).

There's just one little miscalculation in your treatise, Bluesy....it's not the fuel in the cylinder combusting that wears out plugs, it's the spark jumping the gap that wears 'em out, and the shared-coil design fires the plugs every revolution, so (theoretically) an FJR plug WOULD wear out in half the time a non-shared-coil design plug would. So while the plug only ignites the fuel/air charge every other revolution, on the compression stroke, the plug still fires across the spark gap EVERY revolution, compression and exhaust strokes, doubling the "wear out" speed.

I learned something new!

I didn't realize this was a wasted spark system. I thought the FeeJ in this day and age of technology was much smarter and had electronic firing via the com-puter. I haven't got into the ignition system of the bike (no need too). OK. I get it, I stand corrected, thanks RH.

RH speaks with un-forked tongue. (Worrying, but true

. )

Piccy derived from manual shows plug circuit:

 

[Dr. Bones]

I always learn alot on this forum, I love it!

I replaced my OEMs with Iridiums last week and no I can't tell a difference, but I don't have to feel it to know it works! It's interesting to see how far you can go without a change, but at $40 a set, I couldn't care (watch me get flamed for that comment).

If the manual says change it, I'm going to.

My bike is my corvette race car and I'm going to treat it right :yahoo: .

YMMV.

 

[08FJR4ME]

I change mine every spring whether I need to or not. ( Stock plugs ) Less than $25.00 from Yami dealer.

 

[UHOH]

At lunch today a rider asked me if I'd noticed a change after the new plugs at 24,000 miles - and I'd forgotten to mention in the OP

that I didn't detect any performance difference new plugs vs. old plugs.

Same as Dr Bones' post, 2 posts up...